如何在一个窗体中定义另一个窗体的事件,急~~~@!

对于上面给出的窗体,我想让用户登陆到此界面后将选择的信息能添加到数据库中,现在添加倒是可以实现,但是无法实现一一对应问题,就是说我无论用新用户还是老用户登陆,所选择出来的新信息都会显示在一行里,哪怕再次输入也一样,前面选择的信息将被覆盖,怎么样才能实现一一对应呢?以下是我这个窗体设计的代码.

    Imports System.Data
Imports System.Data.OleDb
Public Class Form6
    Inherits System.Windows.Forms.Form
    Dim str As String = ""
    Dim str1 As String = ""
    Dim str2 As String = ""
    Dim str3 As String = ""
    Dim str4 As String = ""
    Dim str5 As String = ""

    Public Function GetSqlStr(ByVal str As String) As String
        Return Replace(str, "'", "''")
    End Function
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.Close()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Hide()
        Dim yourform As New Form8
        yourform.Show()
    End Sub

    Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click
        Dim selectcmd As String = "select * from 注册登陆数据库 where id_number=2"
        Dim connStr, updateCmd As String
        connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=database1.mdb"
        Dim conn As OleDbConnection, cmd As OleDbCommand, myreader As OleDbDataReader
        conn = New OleDbConnection(connStr)
        conn.Open()
        cmd = New OleDbCommand(selectcmd, conn)
        myreader = cmd.ExecuteReader
        If myreader.Read Then
            str = myreader.Item("name1")
        End If
        conn.Close()
        conn = New OleDbConnection(connStr)
        conn.Open()
        updateCmd = "update 注册登陆数据库 Set course1='" & str1 & "',course2='" & str2 & "',course3='" & str3 & "',course4='" & str4 & "',course5='" & str5 & "'  where name1='" & str & "'"
        cmd = New OleDbCommand(updateCmd, conn)
        cmd.ExecuteNonQuery()
        MsgBox("恭喜您，选择类别成功！")
        conn.Close()
    End Sub

    Private Sub CheckBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)
        If str1 = "" Then
            str1 = sender.Text
        ElseIf str2 = "" Then
            str2 = sender.Text
        ElseIf str3 = "" Then
            str3 = sender.Text
        ElseIf str4 = "" Then
            str4 = sender.Text
        ElseIf str5 = "" Then
            str5 = sender.Text
        End If
    End Sub

    Private Sub Form6_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AddHandler CheckBox1.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox2.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox3.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox4.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox5.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox6.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox7.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox8.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox9.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox10.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox11.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox12.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox13.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox14.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox15.CheckedChanged, AddressOf CheckBox_CheckedChanged
        AddHandler CheckBox16.CheckedChanged, AddressOf CheckBox_CheckedChanged
    End Sub
End Class --------------------编程问答-------------------- 你的id_number跟name1有什么关系呢

补充：.NET技术 ,  VB.NET